Combining action and comedy with the supernatural genre, The Testament of Sister New Devil is a high octane romp about a high school boy and his two succubi step-sisters. When his oddball father suddenly decides to remarry, high school student Toujo Basara is about to acquire some very peculiar new family members. Enter his new seductive step-sisters, Mio and Maria. When Basara discovers that one of his step-sisters is a succubus, and his other a recently crowned demon lord, all hell breaks loose! Basara is almost forced into a contract with his demonic sisters where he would act as their eternal servant-but something goes wrong. Instead, a reverse contract is formed, and Basara becomes the master. Between fending off their seductive advances to coping with the attacks of rival demon contractors, Basara has a big learning curve if he is to survive.

The enemy is finally making their move, seeking the Demon Lord’s power hidden within Mio’s body. But during the assault, a pinnacle moment of Basara’s past is revealed, and with it, a true glimpse of his mysterious power--the Banishing Shift! Is the combined strength of Mio and her protectors enough to triumph or have they already reached the limits of their familial bonds?

Demonic step-sisters vie for power and pleasure in this sexy, supernatural comedy spin-off! High school student Toujo Basara’s life has taken a turn for the strange. When his father remarries, a step parent isn’t Basara’s only new family member—he also gets two step-sisters... drop-dead gorgeous step sisters, who also happen to be members of a demon clan. Mio Naruse is a Demon Lord and Mario Naruse her succubus servant. Chaos and passionate antics ensue as Basara gets acquainted with his new demonic siblings, trying to protect them from dangerous demon rivals and struggling to keep up with their lusty, devilish appetites.

With hardly a moment’s rest since saving Mio from the White-Masked Demon, an even stronger enemy has appeared. As the timetable tightens on the new Demon Lord’s reign, he’ll stop at nothing to gain the power that resides in his predecessor’s daughter. Just when it appears Basara, Mio, and Maria may’ve met their match, someone new arrives on the scene--a childhood friend of Basara, who is also from the mysterious hidden village of heroes!

Everything's on the line--Basara and his allies charge headlong into battle against their deadliest enemies yet. Zest brings her full might to bear against them, but even she pales in comparison to the threat waiting in the wings: The dread demon Zolgia! Against a foe so strong, has Basara met his match? He'll need everything in his arsenal to make it out of this one alive!

Basara’s step-sister Naruse Mio possesses the power of a demon lord--a power that is growing stronger by the day, luring demons to Earth. Basara has forged a veritable harem at the Toujou household, living an ideal life together with Mio, the succubus Maria, his two heroic childhood friends, and their demonic servant Zest. But now all that is under threat. What will become of Basara and Mio’s relationship if she is forced to live in the underworld itself? The Testament of Sister New Devil: STORM concludes in this exciting volume!

“People aren’t limited to just one precious thing” Mio, Heiress to the Demon Lord’s Power, begins her battle with the heroes who have been sent to eliminate her. But Basara has a plan to curb the crushing force they have brought. Fight for the things that are precious to you! The mad flashing of swords continues in volume 4!

Combining action and comedy with the supernatural genre, The Testament of Sister New Devil is a high octane romp about a high school boy and his two succubi step-sisters. ALL HELL BREAKS LOOSE! Basara Toujou is hesitant about his father’s sudden decision to remarry, and yet can’t deny it comes with a couple perks–two adorable little sisters. But Basara’s new family isn’t all it appears to be, and when his father leaves on an abrupt business trip, Basara learns that one of his new little sisters, Mio, is actually heir aparent to the Demon Lord, while the other sister, Maria, is Mio’s succubus attendant. Realizing that his sisters are running for their lives from demons, Basara offers to help in any way he can, but ends up getting more than he bargained for in a magical pact with Mio. Surviving demonic attacks is one thing, but can the pair endure the pact’s unique, lustful “side effects”...?

Invaders from another world are attacking the Earth, and humanity's only hope lies in special armors called Hybrid Heart Gears, or HHGs. Hida Kizuna might seem unexceptional, but he has a skill that can turn the tide of battle--by getting female HHG users hot and bothered, he can replenish their energy!

Basara and the rest of the Toujo clan decide it’s time to beat the heat--at the beach! But when Basara and the gorgeous girls that call him master are involved, things are bound to become an entirely different kind of heated. Along with their new servant and houseguest, the reformed demon Zest, the whole crew enjoys some rest, relaxation--and more sensual diversions.